Of course, what the clearest explanation is is very much dependent on one's own background and personal tastes!
For example for this problem I think a lot about sumsets and difference sets anyway, so it made sense to phrase it in those terms.
If you have a suggestion on how it could be rephrased for clarity then please do email in.
There are certainly many Erdős problems, broadly interpreted, still to be added. Any suggestions of missing problems to be added are welcome.
Of course, what the clearest explanation is is very much dependent on one's own background and personal tastes!
For example for this problem I think a lot about sumsets and difference sets anyway, so it made sense to phrase it in those terms.
If you have a suggestion on how it could be rephrased for clarity then please do email in.